Wet clutches of this type have been known in the art for quite a while as converter lock up clutches in hydrodynamic torque converters or as single or twin clutches in a drive train between drive units and transmissions of motor vehicles. Friction energy is generated in particular during slippage of the wet clutch at the friction surfaces providing frictional engagement for the wet clutch. The friction energy heats up the friction surfaces which can damage or destroy the friction liners provided at the friction surfaces and possibly also friction medium that are not integrated in the flow.
Therefore friction liners are being proposed which include grooves with a radial portion so that a pressure medium flow is provided for a defined pressure gradient between a portion radially outside of the friction surfaces and a radially inner portion. The pressure medium flow provides a cooling for the friction surfaces. In order to establish a pressure gradient two pressure cavities can be configured on both sides of the friction surfaces. The pressure cavities are loaded with a variable pressure from the pressure medium. Thus, leakage flows in particular for not yet completely compressed friction surfaces can reduce the pressure medium flow over the friction surfaces during a slippage of the wet clutch during which a forced pressure medium flow due to an increased heat introduction in this operating condition is particularly important.